Slide, please, Gaetano.

All right. And now we are back to our main speakers for today.

Again, as I mentioned at the beginning, our incredible fellow team, they all have

a number of projects ongoing and have been presenting all around the country and

the world. So we get to hear some of their recent work that was presented at the CNS.

And Gaetano, I think you're going to be going first.

Is that correct?

Yes, sir.

All right.

Let me share my screen.

All right. Good morning, everyone.

So today I'll be presenting on our initial results of precision treatment of

postoperative CSF leaks with ultrasound-guided epidural blood patch.

And this is a talk that I gave as an oral presentation at CNS in Austin,

and really was a work of the entire spine team here at Mayo Clinic Florida.

Florida, as well as Dr. Clendenon and James West.

I don't have any disclosures relevant to this talk.

As you know, incidental durotomy is a very well-known complication of spine

surgery, and if left untreated, it can lead to a persistent CSF leak or

pseudomeningocele. The reported rate of incidental durotomy ranges from 4 to 16%,

depending on the index operation.

If patients develop symptoms of persistent CSF leak,

first-line treatment is bed rest.

Other options include oversewing the wound and placement of a lumbar drain,

and there is the potential need of having to go back to the OR for direct repair.

While epidural blood patches are routinely used to treat post-anesthesia or post-LP CSF

leaks, they are not often used after spine surgery for durotomy repair.

The ultrasound is a great technique that allows radiation-free and

direct real-time visualization of the pseudomeningocele,

the dura, and the Tuohy needle.

But this application in the native spine is often very limited.

That's magnified in the postoperative spine,

thanks to the bone work that has been done by removing the bony anatomy and the ligamentous

there, which allows a window for the ultrasound and for the needle to be

visualized properly. So in our study, we did a retrospective analysis of patients

that underwent the US EBP at Mayo Clinic Florida from 2009 to 2020

for symptomatic pseudomeningocele secondary to spine surgery.

We collected demographic, procedural, and outcome characteristics.

The primary outcome of our study was ultrasound EBP success,

defined as a resolution of the initial symptom that brought the pseudomeningocele to clinic.

clinical attention, such as postural headaches,

incisional leak. For our technique, patients are positioned prone.

The ultrasound is used to localize the pseudomeningocele,

and the color Doppler can also be adopted to determine if there are any active sites of

CSF leak of egress. Under ultrasound guidance,

An 18-gauge Tuohy needle is advanced into the pseudomeningocele and the content is

aspirated. The needle is then advanced into the epidural space,

and about 30 mL of autologous blood is injected epidurally in 5 to 10 mL aliquots

under continuous ultrasound guidance.

Then, after waiting for 5 to 10 minutes to allow the blood patch to set,

The ultrasound is then used again to confirm the placement of the patch, and the color

Doppler can also be used to confirm an absence of CSF egress if that was previously

identified. Overall, we had 48 patients who underwent a total

of 61 US EBPs. And you can see that the most frequent index operation was a laminectomy,

24.5%, and about 36.7% of these cases were revision surgeries.

And also that the incidental durotomy was unrecognized during the surgery in about 22%

of cases. You can see here that the median time from surgery to symptom development was

seven days, and the most frequent symptoms at presentation were

postural headaches in 64% of cases and incisional leak in 26.5% of cases.

Here, looking at the results of the EBP under ultrasound guidance,

You can see that 51% of patients experience resolution of their symptoms after their first

blood patch, and you can see that the median volume aspirated from the pseudomeningocele

was 34 mL, and also that another 20% of patients experience resolution of their

symptoms after subsequent attempts of blood patches.

Talking about complications, we had about 14% complications in our series,

And the most frequent one was wound infection in two patients,

followed by meningitis also in two patients.

Here is a couple of illustrative cases you can see here.

Patient that presented with a dural AV fistula.

And here on the T2 sagittal MRI you can see a fairly large pseudomeningocele.

After the patient had undergone the laminectomy and obliteration of the AV

fistula, the patient underwent an ultrasound epidural blood patch.

The contents of the pseudomeningocele was aspirated and a blood patch placed.

And then you can see on the postoperative MRI,

sagittal and axial cut that was done one month after the procedure.

complete resolution of the pseudomeningocele.

This is another case of a patient that laminectomy,

as you can see here on the CT scan on the level above a previous fusion construct,

and there is an hypodensity there, a collection, fluid collection,

that was also again identified under the ultrasound where you can see the star there,

And then the color Doppler was used to identify the active CSF egress there.

The Tuohy needle, you can see here in white where this big arrow is,

is inserted. The content of the pseudomeningocele is aspirated,

as you can see in figure E, and then the blood patch is placed.

And this is a postoperative scan that documents resolution of the

pseudomeningocele. Our study carries all the limitations of all single-institution

retrospective studies,

therefore further prospective and multicenter studies are needed to confirm the

generalizability of our data.

But our study is the first and the largest series describing the adoption of US EBP in

in patients presenting with persistent pseudomeningocele and CSF leak

following spine surgery. We found an overall success rate of over 70%,

with a first-attempt success rate of 50%.

So this suggests that the utilization of US-guided EBP in expert hands may allow for

targeted treatment of a large portion of symptomatic postoperative

pseudomeningoceles. Thank you.

Gaetano, that's excellent work.

Congratulations. It's a novel treatment for these non-uncommon problems.

One thing that I realized I never asked Dr. Miller or

Dr. Clendenon: what's the consistency of the blood that you're using as the patch,

And how long is it in between obtaining the autologous blood and actually injecting it?

I don't know about the time between when the blood is drawn and injected, sir,

but most of them, I believe, it may have been done at the same time of the

procedure, sir.

Yeah, but I mean, they aspirate it and then immediately give it.

I was just curious about how thick the blood is. Maybe

Elird, I see Dr. Behrakis who might

Yeah, I do some of these as well.

Okay. Yeah, we go right away for the blood.

So it's right from an IV catheter into the epidural space.

What's really helpful is the Tisseel fibrin glue.

So it's human fibrin blood components that we inject,

and that solidifies much, much quicker and is much more firm.

With the blood, it's thinner and can get into different

crevices, while the fibrin glue is a bit more firm.

So you try to get both properties in there right at the leak.

Excellent. Yeah. Thanks.

Thanks, Tiana, I appreciate that.

Alireza, did you want to give—I see your hand up there.

Do you want to make a comment?

Sorry I can't join on camera because I'm

tied up in the hospital.

But I would like to second those comments.

I've done a couple of these cases with Dr. Clendenon. A lot of times what we do is we

place an arterial line.

So that way we can reliably draw blood right away as soon as access is identified with the

ultrasound machine. Fibrin glue has also been something new

that's been very helpful for these cases.

One question that I had, and this is something that we always worry about, is the risk of

infection and meningitis.

And it's interesting from the data presented,

that was about two, I believe.

Any thoughts on looking at the data and anything that we can

do to make things better or reduce that risk?

Or is this contributed directly to the block itself?

Or were there other circumstances on those two patients that got infections?

Thank you.

Yes, sir. Excellent question. We had about two patients, about 4% for

our series. It's a small series, so it's difficult to generalize if that's

really a 4% for the procedure itself.

But that was assumed to be related, it was meningitis,

assumed to be related to the procedure, not like a UTI or any other infections.

Let's see. We have a question from Dr. Vargas about what

about the presence of fibrous tissue after the procedure?

And I think

So these are usually done

in scar, that sort of thing.

Yeah, so these are usually done right after the procedure, it's not too long.

And that's why it's very difficult to do them anatomically guided.

That's why the ultrasound really helps to visualize the anatomy.

And as far as we didn't have any issues as far as going through fibrous tissue for

the patches.

Great. Well, thank you so much, Gaetano.

A couple more points here.

Dr. Dean mentioned, would emphasize the need to make sure patient is afebrile and has

normal white blood cell count prior to the blood patch.

I know that's part of the protocol and a good point.

Some of these patients are immediate post-op.

They have an immediate postoperative status, so they might have an elevated white blood

cell count just from surgery.

Very, very good point.

All right. Excellent work, Gaetano.

And we will go on to the next presentation.

We have Dr. Garcia who is going to be presenting next.

Can you see this, Dr. Fox?

Yes.

It's advancing by itself.

All right. Good morning, everyone.

Today I'm going to be presenting on SPECT CT as a predictor of pain generators in patients

undergoing intra-articular injections for neck and back pain.

I think most of you already know of this project.

It's a project that we did with the spine group under particular mentorship of

Dr. Abode-Iyamah, and we presented it at Austin at the Congress of Neurological Surgeons.

As you know, low back pain and also neck pain,

but there's a lot more literature on low back pain, is one of the main leading causes of

disability in general, and yet the identification of painful

generators is still difficult.

Despite use of multiple morphological-based studies,

including X-ray, CT, MRI, and also compounded by the fact that sometimes structural

abnormalities found on scans have no direct correlation with the actual

pain of the patient, which makes the correct identification of the painful generator

difficult and therefore the targeted treatment for that painful generator also

difficult and limited.

With this in mind, there has been some interest in functional-based tests like SPECT

to accurately identify those painful generators,

More recently, a scan has been available which is called the hybrid SPECT CT,

which at Mayo we have been fortunate to have available for a number of years and with good

quality, as I'm going to show in one of the example scans.

So the idea here was to look at facet joint injections,

targeted injections, and see whether or not the hypothesis that injections targeted at

positive sites of uptake would do better than injections targeted at foci without uptake.

To accomplish this, we designed a study with a single institution

retrospective in which we compared both short and long-term outcomes for patients

undergoing facet joint injections for neck and back pain.

Given the large sample size, I was able to do a propensity score match

to adjust for age, gender, BMI, hypertension,

and multiple target injections and injection location.

We did exclude sacroiliac joint injections, given that they are a bit different and they

should not be grouped all the same with cervical, thoracic, and lumbar injections.

So these were our main outcomes.

We looked at immediate positive response, change in VAS two weeks after injection,

improvement in VAS above 50 and 70% after injection, and need for additional treatment,

both injection and surgery.

Importantly, at Mayo, we have people who do call these patients two

weeks after the procedure who are not implicated in the research.

So they're able to give us unbiased feedback from the patient regarding patient-

reported outcomes, which allowed us to really objectify these outcomes.

So as you can see, we have a large number of patients,

2,849 patients that were evaluated with SPECT CT within five years.

Out of these ones, we had 340 with facet injections within 150 days after a SPECT CT.

Why 150 days? We had to choose a threshold.

There is no specific literature on the threshold.

We just had to come up with a threshold that would allow us to look at outcomes that were

associated with the injection and not associated with something else that could

have happened in the interlude.

We had a total of 140 cervical injections,

21 thoracic injections, and 207 lumbar injections.

Importantly, 265 were uptake-targeted injections.

By this we mean that all the injections were targeted at foci of uptake,

all of them. That was our definition of uptake.

targeted injections and 75 were non-uptake targeted injections.

So as you can see here, just an example of a SPECT CT at Mayo,

with in this particular patient, a right L4-L5 facet joint having uptake that was

targeted by injection. This is actually one of the cases that was included in this study.

So here, just some demographics and characteristics of the location and

characteristics of the injection.

As you can see, even though there's nothing that is statistically significant,

it can always compound and have an effect, a confounding effect on the variables.

Hence why we did the propensity score match to adjust for all these variables.

And what you can see here is that both on a univariate analysis and a multivariate

analysis, we did not find statistically
significant differences between non-uptake

and uptake-targeted injections.

But when we did look at patients who already
had a failed injection before the SPECT CT

and in which the surgeon or proceduralist
was able to change the target based on

the information of the SPECT CT.

Below, what you can see is that in those patients we do have a benefit.

And the benefit was particularly greater if there was any change made on the target.

So that is very suggestive that for a particular set of patients with adequate

patient selection, you do see a benefit with SPECT CT to guide facet joint injections.

So basically our conclusions seem to support that, pending adequate patient selection,

SPECT CT has a benefit in guiding facet injections.

There are limitations, of course, with our retrospective single

institution study, but we did use a propensity score to match for confounding

variables. We have a large sample size, but of course future directions would have to

be prospective, multi-site, hopefully double-blind clinical trial to

to accurately discern the impact of SPECT CT in routine clinical practice. And I'll take any

questions.

Excellent, Diogo. Really fabulous work.

And I think this is there's so much potential applicability to using imaging

biomarkers for better delineating patients' pain.

Even with the precision of these SPECT

studies, it shows how challenging it can be to figure out pain generators in the spine.

And I think this is incredible work with a lot of promise. Based on what you've seen so

far, who do you think?

Do you think we should be doing this more or less?

Or do you think people should have this upfront?

How do you recommend we use this based on your knowledge of the technique in

our everyday practice?

So the patients that I did see have a benefit were patients in which there had already

been an attempt at an injection.

Because my understanding is that SPECT CT is sensitive but not necessarily specific.

So it's difficult to figure out which of those facets that are lighting up are the ones

that are actually causing pain.

So when we have the benefit of having a patient that already had a procedure that

failed, we do know which of those joints did light up.

but they're not the actual pain generator.

So we can take those out and pursue the next ones.

So I do see SPECT CT not as a necessary first line for any patient that has a first

procedure, but for a recurrent facet injection.

For a patient who has not benefited from a facet injection,

I would definitely see benefit there. But of course,

I think to actually make a recommendation, we'd have to have a double-blind clinical

trial so we can make a recommendation. Hopefully coming.

Hopefully so.

Yeah, and we'll continue to learn more about these imaging biomarkers.

which I think will be very helpful.

Dr. Deen makes a great point in the comments as well that we have extremely high

quality SPECT studies at Mayo, which

I completely agree. At UF, we didn't do this at all.

So this was something novel to me.

seeing here and very impressed with the quality of these studies.

Excellent work. All right.

I think we can move on now to our next presentation.

Dr. Vivas Buitrago, who is going to be speaking about supra-

marginal resection impact on overall survival for IDH wild-type glioblastoma.

Perfect. Can you hear me now?

Yes. Yes. Thank you, Diogo.

Let me share the screen here.

All right. Are you seeing my slide?

Yes.

Perfect. Good morning, everyone.

Thank you for attending to this lecture today.

So I'm going to present our study that we presented in October this year in CNS.

The title of this study is Supramarginal Resection Impact on Overall Survival for IDH wild-type

glioblastoma according to their cell density distribution infiltration profile.

This is a mathematical model.

We have no disclosures for this lecture.

A bit of background regarding the extent of resection in glioblastoma.

We know that not long ago, the most common surgical recommendation for glioblastoma was

to perform only a biopsy.

And this was not only in the United States but worldwide.

Since the 2000s, we started seeing very important studies from Dr. Lacroix,

from Dr. McGirt, from Dr. Sanai, from UCSF with Dr. Berger,

and from Dr. Chaichana and Dr. Quiñones.

With this data from Hopkins, all of these studies were in favor of performing more

extensive surgical resection on patients with glioblastoma,

and the results were pretty much homogeneous,

identifying that resections above 78% of the contrast enhancement in T1 were associated with

a significant improvement in overall survival in patients with GBM.

But furthermore, we see that the gross total resection is a

is this complete surgical resection of the contrast-enhancing component of the

tumor that you can see up here.

But what about the FLAIR component in the T2 sequence? That we have known for

a while already that there are infiltrated GBM cells within the brain tissue

that most of the time is not being taken care of,

resected because of the infiltrated behavior of these

cells within functional brain tissue that if you resected it,

you can cause a deficit in the functionality of the patient.

So we aim with our group at Mayo Clinic to start looking at the extent of the

supramarginal resection beyond the margins of the contrast-enhancing tumor.

We have seen that regarding this topic, that has been influenced by the

results from the good results from external resection beyond

the margins in low-grade gliomas.

We see here very important papers from MD Anderson,

from Hopkins, from Cleveland Clinic, and from UCSF.

And not all of them have homogeneous results,

as we found before in the gross total resection for the T1 contrast.

So we wanted to give it a shot.

And thanks to all the data that we have at Mayo Clinic with the

high flow of patients, we were.

We were able to do this study in which we identified more than 800 patients.

And we selected only those patients that were IDH wild-type,

since it's the most aggressive type of GBM that has a less overall survival in total.

So we only selected those patients that had a gross total resection of the contrast

enhancement and that they did present before the surgery with some degree of preoperative

So in total, we included 101 patients.

We performed all volumetric analysis on all the sequences in the

contrast enhancement, in the necrosis part, and in the FLAIR for all the patients.

And we did find in univariate and multivariate analysis that increasing SMR as

a continuous variable, for the first time we can show that it is statistically

significant for an increase and improved overall survival in our patient population.

Furthermore, when we performed a threshold analysis,

we found that those resections above 20% and less than 60% were the ones that were related

with a significant increase in overall survival.

So to summarize our findings, we did this illustration that shows

In the green part, in the green portion, are the

percentages from above 20 and less than 60%
that were related with an improved overall

survival. And we didn't find a significant
benefit in those resections above 60%,

that is the red portion of the figure here.

So now we know that increasing SMR is
beneficial for an

improved overall survival in our patients with IDH wild-type GBM.

But we know that there is also a high variability in the radiological presentation

of our group in general in GBM, but also in IDH wild-type.

So we partnered with the Mathematical Neuro-oncology Laboratory at Mayo Clinic Arizona,

with Dr. Kristin Swanson to try to further personalize the

to try to be more specific with using specific patient characteristics from

the radiological data.

And we can see that following our hypothesis at the center of the

lesion, the one that is in close proximity with

the contrast enhancement part has a greater tumor burden cell concentration over there.

And once you are going to the periphery, you see that the density

of these tumor cells is lower.

So this is the formula that was used in our patient population.

In summary, for the interest of time, you can see that in the T1 with contrast, the

volume was approximated to a spherical shape.

And we saw that this portion has a greater cell density compared to the

cell density in the T2 FLAIR.

So with these results, we classified our patient population in three

groups that were nodular, moderately diffuse,

and highly diffuse according to their

to their tumor cell density and distribution profile.

So this is a representation from some of the patients that were selected and classified

and included in these three groups.

You can see here in the nodular, they have more contrast enhancement than FLAIR.

And see in the moderate diffuse, you see that there is some more FLAIR in

the patients surrounding the post-gadolinium T1, and in the highly diffuse

you see that the FLAIR is greater than in the other groups.

So for this, in the univariate analysis, we saw that this was significant,

statistically significant only for moderate and diffuse and highly diffuse.

But it was not significant for nodular.

This is in univariate, and the same results were obtained for the multivariate analysis.

It was statistically significant for moderately and highly diffuse, not for nodular.

But when we performed a threshold analysis, we saw that for the nodular, there is actually a

benefit only in resections from 80 to 100%.

And this is kind of logical because

In the nodular, there is not much FLAIR,
as we showed you in the

MRI before. So there is not much
benefit in extending resection beyond the 20%

of the contrast enhancement in the
nodular group.

In the moderately diffuse,
we found benefits from all the way up to 50%,

as you can see here. And in the highly
diffuse,

We only saw benefits beyond 30% all the way up to 90 and 90 plus percent.

So this is very important because now we can,

based on this study, at least in these results,

we see that there is a very important benefit in the

supramarginal resection of these patients.

And of course, based on their radiological characteristics before the surgery,

the surgeons can decide how much the patients can need,

a resection, an extent of resection based on this.

And for example, in these highly diffuse tumors,

we found that this is the maximum SMR correlated with a beneficial overall

survival. You can see that the patients that had a resection above 90% had a

better overall survival than the ones that had less than 90%.

And this patient population had a greater survival of,

if I remember correctly, almost nine months greater than the patients

that had a resection with less than 90%. For the moderately diffuse,

The highest SMR percentage was 50,

and this patient presented with a benefit

of an additional seven months.

And in the nodular patients, the highest maximum significant